2-14C-1-Allyl-3,5-diethyl-6-chlorouracil II: Isolation and structures of the major sulfur-free and three minor sulfur-containing metabolites and mechanism of biotransformation.

Article abstract of DOI:10.1002/jps.2600710814

The metabolites of 1-allyl-3,5-diethyl-6-chlorouracil in rabbit urine were isolated by preparative thick-layer, liquid-column, and gas chromatography. With the aid of mass and 1H-NMR spectra, and by comparison with an authentic sample, the major metabolite, 1, was identified as 6,8-diethyl-2-hydroxymethyl-tetrahydrooxazolo-[3,2-c]-pyrimidine-5,7(4H,6H)-dione, Metabolite 2 as 1-allyl-3-ethyl-5-(1-hydroxyethyl)-6-methylthiouracil, Metabolite 3 as 1-allyl-3,5-diethyl-6-methylthiouracil, and Metabolite 4 as 6,8-diethyl-2-hydroxymethyl-tetrahydrothiazolo-[3,2-c]pyrimidine-5,7(4H,6H)-dione. The mechanism of the formation of sulfur-containing metabolites is discussed, and a new metabolic pathway for the formation of methylthio compounds is proposed.